Most harpists In North America and Europe are familiar with the conventional taper pin tuning described below. I offer two styles of this traditional method. There is, however, an entirely different choice–the guitar-style machine tuner. I use both, each where appropriate.
Tapered Pins - This is the traditional style of holding the string taught. The tapered pin is jammed into a tapered hole until it is snug enough to not slip against the pull of the string. It requires a tuning wrench to tune the strings. I make stainless steel tuning pins, which are expensive but look and feel great. Typically, the pins go all the way through the neck of the harp. This creates a possible strength issue in the neck, which often must be reinforced. This I do on the Gwydion.
Same-Side Staggered Tuning - This leaves the neck more intact and therefore greatly stronger. This is available on the Rhiannon.
Conventional Through-Tuning is available on all harps of the Bardic Series. This is preferred by harpists who are already used to one style of tuning.
Guitar-Style Machine Tuners - My Hybrid Series uses fine guitar-style machine tuners on each string. So why machine tuners? First and foremost, it means you can tune in real time, WHILE YOU'RE PLAYING! No more having to stop, pick up your tuning wrench (maybe dropping it on the box), tune the string (after craning your neck to see if you're on the right pin–and don't forget that clacking noise when you put the wrench on the pin), put down the wrench (and hope you remember it when you're through playing), and cheerily resume playing.
Not convinced? Okay, secondly, you can really fine tune. Fast. No more skipping past the spot with a sticky pin. And the tuners will last or millions of turns always feeling the same and never working their way further in or out of the neck (which changes how pins feel, and therefore tune). And did I mention fast? You'll be amazed at how fast you can tune your harp!
Using machine tuners is another innovation by the Latin Americans, but they tend to use pretty funky ones. It took me a while to find ones I was satisfied with. Mine are sealed. This means a clean look and less dirt in the gears for a smoother feel and less wear. The chrome models have a gear ratio of 14:1, and 18:1 on the gold plated ones. This means a very smooth action. They're color-coded to correspond with the red and blue strings which means you can grab the tuner you want on the fly (a small but, I think, exceedingly clever innovation).
Once you're on a harp with machine tuners for any time at all, you'll loathe going back to the tuning wrench (which you've probably mislaid by now anyway).